Casting mold having beveled end faces on inner walls

ABSTRACT

A casting mold for producing a hollow component having apertures and inner walls is provided, in which the casting mold has at least one inner wall element having apertures, into which liquid metal can also propagate, wherein at least one inner wall element has an end face in the region of the aperture, which end face is beveled and which runs at an angle differing from 90° to a propagation direction of the liquid metal or of side surfaces of the inner wall elements in the casting mold. Accordingly, the propagation front of liquid material in the casting mould is influenced by a specific modification of the end faces of inner wall elements and influences or the formation of oxide layers are displaced to less critical regions of the casting portal to be produced.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the US National Stage of International Application No. PCT/EP2013/072382 filed Oct. 25, 2013, and claims the benefit thereof. The International Application claims the benefit of European Application No. EP12193768 filed Nov. 22, 2012. All of the applications are incorporated by reference herein in their entirety.

FIELD OF INVENTION

The invention relates to a casting mold having on the inside walls with beveled end faces.

BACKGROUND OF INVENTION

Casting molds for producing hollow components having inner structures, such as in the case of turbine blades, often have a plurality of ducts, into which liquid material propagates.

In this respect, gaps which represent connection elements in the later cast part are present between individual duct walls of the casting mold.

Here, an oxide layer often forms in this region because two liquid fronts collide in this intermediate region, these then forming an oxide film layer in this thin region.

SUMMARY OF INVENTION

It is therefore an object of the invention to solve the aforementioned problem.

This object is achieved by a casting mold as claimed in the independent claim.

The dependent claims list further advantageous measures which can be combined with one another as desired in order to achieve further advantages.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawing:

FIG. 1 shows a casting mold according to the prior art,

FIGS. 2, 3 show casting molds according to aspects of the invention.

DETAILED DESCRIPTION OF INVENTION

The description and the figures represent only exemplary embodiments of the invention.

FIG. 1 shows a casting mold 1′ according to the prior art.

A propagation direction of a liquid metal introduced into the casting mold 1′ or the longitudinal direction of outer wall elements 4′, 4″ and inner wall elements 7′, 7″ of the casting mold 1′ is denoted by the reference sign 19.

The propagation direction 19 runs virtually parallel to the walls 4′, 4″, 7′, 7″ (FIGS. 1, 2); 103′, 103″, 106′, 106″ (FIG. 3).

The casting mold 1′ according to the prior art has the inner wall elements 7′, 7″, which lie opposite one another as seen in the propagation direction 19 of the liquid metal to be poured in, the metal which has solidified in the casting mold 1′ between the outer wall elements 4′, 4″ of the casting mold 1′ giving rise to walls 2′, 2″ of a cast component.

The inner wall elements 7′, 7″ have an aperture 13′ for two arriving liquid fronts 22′, 22″, into which 13′ the liquid metal penetrates and thereby forms an inner structure 25′, i.e. a connection between the walls 2′, 2″ of the later cast component.

Liquid fronts 22 ^(V), 22 ^(VI) which have propagated are present in the region of the aperture 13′. A dashed line indicates the contact line 20′ of the liquid fronts 22 ^(V), 22 ^(VI), these not coalescing optimally in terms of melt metallurgy in the aperture 13′, possibly on account of oxide films on the liquid fronts 22 ^(V), 22 ^(VI). Thereafter, the liquid fronts 22′″, 22 ^(IV) run again as previously (=22′, 22″).

An end face 10′ of the inner wall element 7′ and an end face 10″ of the opposing inner wall element 7″ are formed perpendicular to the propagation direction 19.

Cracks sometimes arise within the aperture 13′ if the metal solidifies in the inner structure 25′ of the filled aperture 13′ along the dashed line.

FIG. 2 shows a casting mold 1 according to the invention, in which, in comparison to FIG. 1, an end face 40 of an inner wall element 31 (analogous to 7′) has a different form.

The end face 40 is beveled and runs at an angle differing from 90° to the propagation direction 19 or to the outer surface 50 of the inner wall element 31.

It is advantageous that that end face 40 of the inner wall elements 7″, 31 around which the liquid front 22′, 22″ passes first is beveled.

By virtue of this asymmetrical configuration of the end face 40 of the wall element 31, the liquid front 34, 37 of the liquid material is influenced, and an aperture 43 according to the invention, in which the two liquid fronts 34, 37 collide, is shifted with its contact line 60 away from the beveled end face 40 and away from an aperture 43 between the end faces 10″, 40 of the inner wall elements 7″, 31 into a mechanically less critical region, such that a cast part with walls 54′, 54″ which has a higher strength is formed.

Similarly, the end faces 112′, 112″ of in particular parallel inner wall elements 103′, 106′; 103″, 106″ running alongside one another can be beveled (FIG. 3), these then being at an angle differing from 90° to the side surface 51′, 51″.

A further inner wall 55 is formed between the inner wall elements 103′, 106′, 103″, 106″ upon solidification of the metal.

End faces 109′, 109″ of the wall elements 103′, 103″ lying opposite the beveled end faces 112′, 112″ are advantageously not beveled, but instead run perpendicular to the propagation direction 19 or to the side surfaces 51′, 51″ thereof.

Apertures 53′ and, respectively, 53″ are present between the inner wall element 103′, 106′ and 103″, 106″.

It is advantageous that all end faces 112′, 112″ are beveled to the same side.

The angle of the beveled end faces 40, 112′, 112″ to the propagation direction 19 can advantageously be between 45° and 60°.

The side to which the beveled end faces 40, 112′, 112″ face is immaterial.

It is advantageous that the entire end face 40, 112′, 112″ is beveled. 

1. A casting mold for producing a hollow component having apertures and inner walls, in which the casting mold has at least one inner wall element having apertures, into which liquid metal can also propagate, wherein at least one inner wall element has an end face in the region of the aperture, which end face is beveled and which runs at an angle differing from 90° to a propagation direction of the liquid metal or of side surfaces of the inner wall elements in the casting mold.
 2. The casting mold as claimed in claim 1, wherein the end face is at an angle of 45° to 60° to the propagation direction of the liquid metal or to the side surfaces of the inner wall elements.
 3. The casting mold as claimed in claim 1, wherein the casting mold has a plurality of inner wall elements, wherein a plurality of inner wall elements have a bevel of the end faces, the end faces beveled in particular in each case to the same side.
 4. The casting mold as claimed in claim 3, wherein all beveled end faces are beveled to the same side.
 5. The casting mold as claimed in claim 1, wherein the propagation direction of the molten metal runs at least in places parallel to the inner wall elements.
 6. The casting mold as claimed in claim 1, wherein those end faces of the inner wall elements which lie opposite the beveled end faces of the inner wall elements are not beveled.
 7. The casting mold as claimed in claim 1, wherein the casting mold is made of ceramic.
 8. The casting mold as claimed in claim 1, wherein the beveled end faces are formed at the site where a molten metal propagates first. 